Male Infertility

Male infertility, the inability of a man to produce a pregnancy in a woman, is often caused by measurable deficits in sperm function or sperm count. In about half of all cases, however, the source of the problem is never discovered.

The good news is that, without any treatment at all, about 25% of supposedly infertile men bring about a pregnancy within a year of the time they first visit a physician for treatment. In other words, infertility is often only low fertility in disguise.

Proposed Treatments for Male Infertility

Carnitine

Growing, if not entirely consistent evidence, suggests that various forms of the supplement
L-carnitine
may improve sperm function and thereby provide benefit in male infertility.
12-20,27,32,33,44-45,52

For example, in one double-blind study, 60 men with abnormal sperm function were given either carnitine (as L-carnitine 2 g/day and acetyl-L-carnitine 1 g/day) or placebo for 6 months.
34
The results showed significant improvement in sperm function in the treated group as compared to the placebo group.

A similarly sized 6-month, double-blind, placebo-controlled study, which involved men with low sperm counts, found benefits with carnitine (again as L-carnitine 2 g/day and acetyl-L-carnitine at 1 g/day) taken alone or carnitine combined with the anti-inflammatory drug cinnoxicam.
35

In addition, a 2-month, double-blind, placebo-controlled, crossover study of 100 men with various forms of infertility found probable benefits with 2 g daily of L-carnitine.
36

Zinc Plus Folate

A 26-week,
double-blind, placebo-controlled
trial compared the effects of treatment with zinc (66 mg of zinc sulfate, supplying 15 mg of zinc), folate (5 mg), and zinc plus folate against placebo.
22
A total of 108 fertile men and 103 men with impaired fertility (“subfertile men”) participated in the study. The two supplements combined significantly improved the sperm count and the percentage of healthy sperm in the subfertile men; neither supplement alone produced this effect, and there was little effect of the combined therapy on fertile men.

Another study also found potential benefit with zinc plus folate.
46

For more information on dosage and safety issues, see the full articles on
folate
and
zinc
.

Vitamin B
12

Mild vitamin B
12
deficiencies are relatively common in people over 60.
1,2
Such deficiencies lead to reduced sperm counts and lowered sperm mobility. Thus vitamin B
12
supplementation has been tried for improving fertility in men with abnormal sperm production.

In one double-blind study of 375 infertile men, supplementation with vitamin B
12
produced no benefits on average in the group as a whole.
3
However, in a particular subgroup of men with sufficiently low sperm count and sperm motility, B
12
appeared to be helpful. Such "dredging" of the data is suspect from a scientific point of view, however, and this study cannot be taken as proof of effectiveness.

For more information, including dosage and safety issues, see the full
Vitamin B
12
article.

Antioxidants

Free radicals, dangerous chemicals found naturally in the body, may damage sperm. For this reason, a number of studies have evaluated the benefits of
antioxidants
for male infertility.

In a double-blind, placebo-controlled study of 110 men whose sperm showed subnormal activity, daily treatment with 100 IU of
vitamin E
resulted in improved sperm activity and increased rate of pregnancy in their partners.
6

Preliminary studies suggest that
vitamin C
may improve sperm count and function.
7
However, a recent double-blind study of 31 individuals that tested both vitamin C and vitamin E found no benefit.
8
The dosages studied ranged from 200 mg to 1,000 mg daily.

According to one small double-blind study, the antioxidant carotenoid
astaxanthin
might enhance male fertility.
37
Other antioxidants that have shown at least a bit of promise include
lycopene
,
21
coenzyme Q
10
,
24
and
selenium
.
25

Researchers reviewed 34 randomized trials involving 2,876 couples experiencing unexplained male infertility, as well as sperm-related problems.
54
The couples in the oral antioxidant groups had increased pregnancy rates. Despite these favorable findings, the researchers concluded that these studies alone do not conclusively show that antioxidants are beneficial for male infertility.

A major pharmaceutical company has reported success for male infertility using a miscellaneous mixture of antioxidants.
53
However, there is no reason to believe that the exact mixture of substances contained in this product were chosen with any particular insight; any such insight regarding the optimum formulation does not as yet exist.

Other Herbs and Supplements

The herb
Lepidium meyenii
(
maca
) is claimed to enhance fertility, but the supporting evidence is limited to animal studies and one tiny
uncontrolled study
in humans conducted by a single research group.
38,47-50
Contrary to what is stated on numerous websites, maca does not appear to raise testosterone levels.
28

In a double-blind trial of 28 men with impaired sperm activity, use of docosahexaenoic acid (DHA), a component of
fish oil
, failed to improve sperm health.
9
Another double-blind study failed to find
L-arginine
effective for improving pregnancy rates.
26

One very small study failed to find
magnesium
helpful for infertility.
39

Many other substances have been suggested as treatments for poor sperm function and infertility, including the herbs
ashwagandha
,
Eleutherococcus
,
pygeum
,
saw palmetto
, and
suma
, as well as the supplements
SAMe
and
calcium
, but there is no meaningful supporting evidence for these treatments.

In addition, all of the treatments listed in the article on
Impotence
have also been proposed as treatments for male infertility, though not necessarily with any supporting evidence.

Herbs and Supplements to Use Only With Caution

Soy
or
soy isoflavones
,
29
as well as the herb
licorice
,
10
may reduce testosterone levels in men. For this reason, men with impotence, infertility, or decreased libido may want to avoid these natural products.

One report claims that both
tea tree oil
and lavender oil have estrogenic (estrogen-like) and antiandrogenic (testosterone-blocking) effects.
51
If this were true, men with infertility should avoid use of these herbs. However, a literature search failed to find any other published reports that corroborate this claim.

According to a preliminary double-blind study, the supplement
melatonin
affects testosterone and estrogen metabolism in men, and when taken at a dose of 3 mg daily for 6 months may impair sperm function.
23

Preliminary evidence from animal studies hints that use of some forms of
peppermint
at high doses might impair fertility.
40

There is contradictory evidence from animal studies on whether the herb
andrographis
may impair fertility.
30,31
The same is true of the herb
stevia.
.
41-43

All EBSCO Publishing proprietary, consumer health and medical information found on this site is accredited by URAC. URAC's Health Web Site Accreditation Program requires compliance with 53 rigorous standards of quality and accountability, verified by independent audits. To send comments or feedback to our Editorial Team regarding the content please email us at
HLEditorialTeam@ebscohost.com.

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.